As known so far, the optical recording medium storing information on one side or both sides of it has been used for various purposes, especially in music, game, video and computer industries. Digital information is stored in a form of pits with a predetermined size and interval along the tracks formed on one side or two sides of the disc.
According to “copy managing system of an optical disc”(Korean Patent Application Publication No. 1999-23961), one of the methods already known, manufacturing an optical recording medium as mentioned above, a glass master first is formed by exposing a photoresist spread over a glass substrate using a laser or light. The exposed pattern corresponds to the pattern of the digital information stored in the disc last.
Then an indentation, which is called a pit, is formed in the single spiral of the glass master by removing the exposed area through etching or developing process. The pattern and length of the indentation along the tracks represent the recorded information digitally. And a nickel master, which is a tool for molding duplicates in the following forming process, is then formed by applying the galvanized nickel to the glass master in the electroforming process.
The patterns of the nickel master, generally called a pit and a land (or mirror area) respectively, are formed by transcribing on a polycarbonate or PMMA substrate. The stamped duplicate is coated with a reflection layer and added a protection layer for preventing the reflection layer from oxidizing.
In order to read the optical recording medium manufactured in the manner above, the surface of the disc is irradiated to laser beams, which are oscillated with the predetermined frequency and power. There is a difference of the intensity of the reflected laser beams between in case the beams are applied to the mirror area and in case to the pit, and a reproducing apparatus (which is capable of only reproducing the optical recording medium) including a reading part, called the optical pick-up, recognizes the difference of the intensity of the reflected beams as digital information of 0 or 1 so that the digital information recorded on the optical recording medium can be reproduced.
The optical recording medium has developed from the compact disc (audio CD), which is mainly for reproducing the audio contents, and currently the compact disc is used for storing the data of a computer in a form of the read-only memory (CD-ROM) or reproducing the audio contents in a computer equipped with an audio CD driver by adding computer-readable information to the audio CD.
However, as the information recorded on the optical recording medium can be read by a reproducing apparatus, for example, a CD-ROM driver with which an general personal computer is equipped, the contents on the recording medium are not only reproduced, but also illegal copying of the contents prevails. Therefore, a serious problem how to protect the copyright of the contents on the recording medium rises.
Generally, when the audio CD or the CD-ROM is copied, the information on the lead-in area, namely TOC (Table Of Contents), such as the information stored in the recording medium and the predetermined control information, should be read, so there has been a try to solve the problem above. That is, according to “CD reproducing control method without TOC” (Korean Patent No. 200879), in order to prevent the illegal copying of the information on the recording medium by removing the TOC of the CD-ROM or the audio CD and reproduce both the recording medium prevented from being copied illegally and a general recording medium, it is disclosed that a reproducing control method of a CD without a TOC for preventing the illegal copying, includes the steps of:                (1)verifying whether the TOC is read,        (2)going to a predetermined track and reading information from the track, if the TOC is not read in the step (1),        (3)verifying whether the information, which is read in the step (2), is read from the recording medium without the TOC and        (4)reading in accordance with a new format if the recording medium does not have the TOC, or reading in accordance with a general format if the information is from the lead-in area in the step (3).        
According to the method above, However, there is a problem that it is impossible to reproduce the contents recorded on a copy-protected recording medium only with a general reproducing apparatus, because the TOC of the recording medium should be removed artificially, and the reproducing apparatus should be specially programmed and carried out in accordance with the steps above. That brings users a problem that they have to buy an appropriate reproducing apparatus anew besides the recording medium.